Detent mechanism for pressure regulators



Aug. 3,1948. F. J. WRIGHT DETENT MECHANISM FOR PRESSURE REGULATORS FiledJuly 20, 1944 when the valve parts are in the positions illus.-.

trated in Fig. 2 of the drawings, the valve is effectively closed andthe hydraulic-fluid in chamber 5 is directed through passageway 6 to thesupply line 2.

When in response to pressure in chamber I as hereinafter described morecompletely, the

piston groove or chamber 31 provides a passageway from chamber .5through more 32 to a cir: cumferential chamber 33 formed in. the maincasting 3I which communicates by means of a bore 35 with the drain pipe4 so that whensaid piston I2 is shiftedas aforesaid, the pressure line Iwill be connected to the drain pipe 4. Piston I2 is therefore the finalcontrol member for the valve 30. I

To provide drainage for any leakage and to preventany development ofundesired pressures, particularly on the piston I2, the heads 34 and 36are provided with drain grooves 40 and M, respectively, whichcommunicate with the drain pipe 4 by way of longitudinal bore 42 in themain casting 3I which communicates with bore 39.

Adjacent its right-hand end, as viewed in Fig. 2 of the drawings, thepiston I2 is provided with a pair of spaced peripheral'grooves 20 and-25. The groove 25 is actually open at the right-hand end, but itfunctions the same as though it were closed as is the groove 20.

The main casting 3| is provided with a peripheral groove 43 whichreceives a plurality of coil springs I'I. These coil springs I1 andassociated apparatus co-operate to provide ,an improved type of detentby which the cylinder I2 is releas ably held in either of its twopositions, that is, the unloading position or the loading position, andper se and in combination constitutes an important contribution of myinvention.

Each of the coil springs I'I, if released, would have a straightlinelongitudinal axis down its center. Each spring, however, isbent sothat its longitudinal 1 axisis curved as clearly illustrated in Fig. 3of the drawings. As a consequence, the center inner portion of each coilspring I! rides on the bottom of the groove 20 or 25 of'piston I2,depending on which is opposite the groove 43. The opposite outer freeends of each coil spring I! abut the outer periphery or bottom of thegroove 43, and the outer'portion, as viewed in Fig. 3, is received inthe groove 43 and contained within the side walls thereof; The groove 43has sufficient depth so that when adequate pressure is developed on thepiston-12 to move it, for example,- to the right from the'positionillus-- trated in Fig. 2 of the drawings; each spring I! can #bedeflected, bent or flexed so that its longitudinal axis is bent into anarc of smaller radius, and the outer central portion of each saidsprifig I'I pressed into said groove 43 while the inner central portionof each rides over the projection between the two adjacent grooves 20and 25.

Considering this structurein a slightlydiifer cut-manner and referringparticularly to Figs.

' 43. As the piston I2 moves and the innerportion 4 V 2 and 3 of thedrawings, it is to be noted that the axes of the coil spring I'I lie ina plane which is at right angles to the axis of the piston I 2. Whenthese springs I1 are acting to retain the piston I-2 releasably ineither position, the central inner portion of each coil spring isreceived in a groove or while at leastIa-portion of the entire outerpart of each spring, measured radially from the axis of piston t2,extends in the groove 43. However, the outer central part of each springI I is spaced inwardly from the bottom of the groove 43 or, in otherwords, from the outer peripheral wall thereof. Furthermore, the axis ofeach spring I1: is on a curve, the diameter of which is greater than thediameter of the groove r p of each spring I! is deflected radiallyoutwardly, the piston or cylinder I2 is moved to the right,

its axis bends into a circle of smaller diameter and-practically theentire outer peripheral surface of each spring I1 is in contact with thebottom orouter peripheral wall of the groove '43, while each spring I!is relatively free to roll in the groove 43.

. In the operation of the pressure regulator, if the pressure in theaccumulator 23 and that in the line 2 are below a predetermined maximum,the valve piston I2 will be in the position illustrated in Fig. 2 of thedrawings. Hydraulic fluid undertpressure will be flowing through thepressure line I into the chamber 5 through passageway 6 and past checkvalve which will be open, to the supply line 2 from which it will flowto the accumulator or directly to the brake piston 22 if the valve 2I isactuated to operate it.

As the pressure builds up, due to the delivery of a reat amount of fluidto the accumulator 2-3, this pressure will be communicated to the piston8 through the chamber "I and force the piston 8, shoulder pin I0 andspring guide I8 to the right, as viewed in Fig. 2 of the drawings, tocause compression of the pressure adjusting spring I9. .This movementwill take place for a time without moving the piston I2 from theposition illustrated, and thismovement of the pin III will causecompression of the shifter or snap spring I3 since the washer II willmove with the pin I0, and the opposite or right-hand end of the springI3 is held against the abutting washer III to the piston I2 by means ofsnap ring I6.

After a. predetermined movement of the pin Ilito the right from thatillustrated in Fig. 2 of the drawings, the spacer tube I 4 will abut orstrike the washer III, and further movement of said pin III to the rightas controlled by piston 8 against the compression of spring I9, willforce movement of the piston I2 to theright. During the compression ofthe snap spring I3 the piston- I2 is held in the position illustrated inFig. 2 of the drawings, by the detent formed by the coil springs I1, thegroove 43 which receives it, and the open end groove 25.

Asthe piston I2 is moved to the right, as above described, the ledgebetween the grooves 25 and 20 will force thecenters of the coil springsII outwardly into the grOOVe 43 or, in other Words, bend ordeflect them,and once this movement is started, the energy stored up in the snapspring I3 will cause the piston I2 to movewith a snap action to theright, and the center portions of the coil springs I'I will deflect orbend outwardly as said coil springs I'I roll by a distinct rollingaction over the peripheral projection of the piston I2 between thegrooves 20 and 25,

. It may be noted that this rolling action of the springs I1 providesfor a minimum of wear of said springs as well as of the other detentmechanism, including adjacent portions of piston l2. Each spring I! alsocontributes to a long life and a minimum of wear by virtue of thefurther fact that it has a large area of contact with the bottoms of thegrooves 20 or 25 as well as a large area of contact with the ridge ofpiston 12 between said grooves as to which it comes into rolling contactas the piston I2 shifts.

The aforesaid snap action to the right will continue until roove 20 ofthe piston I2 is opposite the groove 43 of the main body 3|, in whichposition the springs I! will be received in the grooves 20 and thepiston I2 will be releasably detained or held in the by-pass orunloading position thereof.

As previously mentioned, when this shifting action has taken place inresponse to the accumulation of a predetermined amount of fluid in theaccumulator 23, or, in other words, a predetermined pressure in supplyline 2, the piston 12 provides an unloading of the pumping unit 24 byproviding a =by-pass between the pressure line I and the drain pipe 4 byway of chamber 5, bore 32, chamber 31 in piston l2, chamber 38 and bore39.

As the pressure in the supply line 2 decreases or, in other words, asthe volume of stored hydraulic fluid in the accumulator 23 is reduced,pressure on the piston 8 will, of course, be reduced, and the spring 19will force the piston 8, pin l0 and spring guide 18 to the left, asviewed in Fig. 2 of the drawings, whereupon the snap spring 13 willagain be compressed and this action will continue without movement ofthe piston I2 from its unloading position until the spacer tube l4strikes the washer III which in response to continued movement to theleft will produce thesnap action movement of the piston I2, moving itfrom its unloading position to its loading position. This movement willcause the detent springs IT to be rolled from the groove 20 to the openend groove 25.

Obviously those skilled in the art may make various changes in thedetails and arrangement of parts without departing from the spirit andscope of the invention as defined by the claims hereto appended, and Itherefore wish not to be restricted to the precise construction hereindisclosed.

Having thus described and shown an embodiment of my invention, what Idesire to secure by Letters Patent of the United States is:

1. A detent including a body having a cylindrical bore, a shifta'blepiston in said bore, a groove in said body, a pair of grooves in saidpiston selectively positionable opposite said body groove as said pistonis shifted in said bore, a coil spring in said body groove having twoends contacting the bottom thereof and having a longitudinal axis whichis normally substantially straight when said spring is released butwhich is curved by the action of said piston contacting it, said coilspring having direct contact at its inner center portion with saidpiston while being held in said body roove, said body groove havinsufficient depth to permit said piston to deflect said spring whilemoving between its adjacent positions.

2. A detent including a body, a shiftable member in said body, acylindrical groove in said body, a cylindrical groove in said shiftablemember, and a coil spring having two ends and a substantially straightaxis when it is released and positioned in said two grooves with itscenter inner portion contacting the bottom of said cylindrical groove insaid shiftable member groove and its ends contacting the bottom of saidcylindrical body groove and being thereby bent into an arc of a circle,said coil spring bending into an arc of a circle of smaller diameter androlling as said control member moves.

' FRED J. WRIGHT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,158,955 Apple et a1. Nov. 2,1915 1,464,303 Whitelaw Aug. 7, 1923 1,475,619 Barney Nov. 27, 19231,577,498 Spinney Mar. 23, 1926 1,748,298 May Feb. 25, 1930 1,770,912Clapp July 22, 1930 1,893,076 Flygare Jan. 3, 1933 1,976,827 Bone Oct.16, 1934 2,127,293 Gilman Aug. 16, 1938 2,222,346 Eickstaedt Nov. 19,1940 2,264,375 Hill Dec. 2, 1941 2,276,885 Sherlock Mar. 17, 19422,372,016 Rockwell Mar. 20, 1945 FOREIGN PATENTS Number Country Date426,333 Great Britain Apr. 2, 1935

